Determination of the strong-coupling constant from the $Z$-boson transverse-momentum distribution

Abstract

The strong-coupling constant is determined from the low-momentum region of the transverse-momentum distribution of $Z$ bosons produced through the Drell-Yan process, using predictions at third order in perturbative QCD. The analysis employs a measurement performed in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=1.96$ TeV with the CDF experiment. The determined value of the strong coupling at the reference scale corresponding to the $Z$-boson mass is ${\alpha }_S(m_Z)=0.1191_{-0.0016}^{+0.0013}$.

Comments: Included O(${\alpha }_S^3$) matching, simultaneous fit of PDFs and ${\alpha }_S$, and additional uncertainties related to QED, non perturbative effects, and matching to fixed order. Version published by EPJC